Negative tests separate file for floating_ips_actions

Separate negative tests on test_floating_ip_actions.py
Changes on setUpClass to accommodate what is needed on
each file.

Fix possible race condition with server name.

Change-Id: Ie12b1e54ef1358511af76ccbb69878b925efbdd5
Remove unused allow_tenant_reuse flag

Change-Id: Ic4884666965dbe22fb55b12e087dd102345686a1
Merge "Remove unused allow_tenant_reuse flag"
Merge "Negative tests separate file for floating_ips_actions"